Motor vehicle alternator

ABSTRACT

The invention relates to an alternator for a motor vehicle including a stator ( 13 ) equipped with a body ( 14 ) carrying several phases each comprising, on the one hand, an inlet (E 1  to E′ 3 ) and an outlet (S 1  to S′ 3 ) installed outside the body ( 14 ) of the stator ( 13 ), and, on the other hand, electrically conducting elements, which are arranged in a network on either side of the body ( 14 ) of the stator ( 13 ) so as to form a first ( 12 ) and a second ( 12 ′) bun and which pass through the said body, in which the electrically conducting elements are linked together to form the said networks and connect the inlet of the phase to the outlet of the phase by forming at least one winding. According to the invention, one of the buns ( 12, 12 ′), on one side of the body ( 14 ) of the stator ( 13 ), carries three inlets (E 1  to E 3 -E′ 1  to E′ 3 ), an electrically conducting linking part ( 50, 51 ) linking the said inlets electrically together.

FIELD OF THE INVENTION

[0001] The present invention relates to alternators of motor vehicles.

STATE OF THE ART

[0002] As is known, an alternator for a motor vehicle includes a statorequipped with a body carrying several phases each comprising, on the onehand, an inlet and an outlet installed outside the body of the stator,and, on the other hand, electrically conducting elements, which arearranged in a network on either side of the body of the stator so as toform a first and a second bun and which pass through the said body. Theelectrically conducting elements are linked together to form the saidnetworks and connect the inlet of the phase to the outlet of the phaseby forming at least one winding.

[0003] Such a machine is described, for example, in the document WO92/06527.

[0004] In one conventional embodiment, the inlets of the phase windingsare connected in a star or y, the outlets of the phases are linked to arectification and/or control device for rectifying the alternatingcurrent induced into a direct current, while the inlets are linked to aneutral point.

OBJECT OF THE INVENTION

[0005] The object of the present invention is to create this neutralpoint in a simple and economical manner.

[0006] According to the invention, an alternator of the type set outabove is characterised in that one of the buns, on one side of thestator, carries three inlets, on the one hand, and, on the other hand,an electrically conducting linking part of circumferential orientationlinking the said inlets electrically together.

[0007] By virtue of the invention, the inlets are simplified since theydo not have to be extended in order to be linked to a common neutralpoint; this link being formed in a simple and economical manner by thelinking part installed in the vicinity of the body of the stator. Theneutral point, by virtue of the linking part, is integrated in a compactmanner to the stator.

[0008] The phase inlets are advantageously standardised and shorter,which makes it possible to reduce the electrical resistance.

[0009] The linking part allows an increase in the electrical power ofthe alternator.

[0010] The linking part is a lightweight matching piece or a segment ofa piece, which is carried by one of the buns. This part, ofcircumferential orientation, is not very bulky, has a size which dependson the applications and makes it possible to render the stator morecompact. It promotes a reduction in the electrical resistance of thestator and standardisation of the outlets.

[0011] The linking part is fixed by any appropriate means onto theinlets.

[0012] It is possible, for example, to envisage electrically conductingfixings by crimping or bonding.

[0013] Advantageously, the linking part is linked by welding to at leastone of the said to the [sic] inlets.

[0014] The linking part, in one embodiment, features an annular-sectorshape, being fixed onto the inlets. Thus a comb is formed with theinlets.

[0015] For preference, the linking part has an annular-sector shapemounted at the outer periphery of the bun carrying the said inlets andthe width of which is oriented axially.

[0016] The linking part thus consists, in one embodiment, of a simplebar. This bar is advantageously pierced in order to facilitate itsextension and the ventilation of its carrying bun, especially when thebar is of axial orientation.

[0017] This arrangement makes it possible to reduce the bulk of thestator, since it is possible to fix the linking part onto the inner orouter periphery of the inlets.

[0018] For preference, the linking part is installed axially between thevertices of the electrically conducting elements consisting of the axialends of these elements belonging to the bun in question, and the body ofthe stator.

[0019] For example, the linking part is installed axially at thevertices of the electrically conducting elements consisting of the axialends of these elements belonging to the bun in question.

[0020] Advantageously, the linking part is a linking piece linking theinlets.

[0021] For preference, the inlets each comprise a free part of axialorientation, the linking piece linking these free parts.

[0022] Advantageously, the inlets each comprise a free part ofcircumferential orientation, the linking piece linking these free parts.

[0023] For example, two inlets are linked by a pin, the linking partconsisting of an end portion of the third inlet curved over in thecircumferential direction and being welded onto the said pin.

[0024] For preference, the said two inlets linked by the said pin areconsecutive, when following the periphery of the bun.

[0025] Advantageously, the said two inlets formed by the said pin arenot consecutive when following the periphery of the bun, the said thirdinlet being linked to the said pin by a peripheral end portion.

[0026] For example, the linking part is extended by a free portion ofaxial orientation.

[0027] For preference, the linking part constitutes a circumferentialextension of one of the three inlets.

[0028] For example, the other two inlets are linked to the linking partin each case by a circumferential end portion.

[0029] In order to reduce the bulk as much as possible, the inlets andthe linking part are installed on a circumference of different diameter,for example greater, than that on which the three outlets associatedwith the inlets are installed.

[0030] In a variant, the inlets and the outlets are installed on thesame circumference.

[0031] Advantageously, the outlets belong to the same bun as the inletsand extend in axial projection with respect to the inlets equipped withthe linking part, this in the opposite direction to the body of thestator.

[0032] The windings of electrically conducting elements may be of thetype with separate coils or with overlapping coils, of the undulatingand/or imbricated type. Advantageously, the windings are of the typewith bars in order to obtain buns of short length, facilitate the fixingof the linking part and obtain heavy currents at low voltages. The barsare advantageously overall of rectangular cross-section in order toincrease the cross-section of electrically conducting elements andfacilitate the fixing of the linking part on the inlets.

[0033] For example, the electrically conducting elements, the inlets andthe outlets are in the form of bars.

[0034] Advantageously, the electrically conducting elements, the inletsand the outlets are in the form of bars of square or rectangularcross-section.

[0035] The stator with a linking part according to the invention isfitted in all types of alternator.

[0036] The alternator may include more than three phases.

[0037] For example, the alternator, in one embodiment, is of thesix-phase type.

[0038] All combinations are then possible. In one embodiment, the sixphase windings have inlets connected to a neutral point as described,for example, in the document FR-A-1 541 530. In this case, the linkingpart links together the six inlets. In a variant, two series of threephases linked to two rectification devices are provided, as described,for example, in the documents FR-A-2 687 861. The alternator is thenequipped either with two linking parts when each series of three phasesincludes a neutral point, or with one linking part when one of theseries of three phases includes a neutral point and the other series ofthree phases includes windings mounted in delta mode.

[0039] Each phase, in one embodiment, includes at least two windings asdescribed, for example, in the documents EP-A-0 762 603 and WO 92/06527.

[0040] Advantageously, the linking part is produced on the basis of anelectrically conducting element.

[0041] The inlets and the linking part, in one embodiment, are installedon one side of the body and the outlets on the other side of the saidbody.

[0042] Advantageously, in order to simplify the windings, the inlets,the outlets and the linking part, in another embodiment, are installedon the same side of the body of the stator.

DESCRIPTION OF THE DRAWINGS

[0043] The description which will follow illustrates the invention inthe light of the attached drawings, in which:

[0044]FIG. 1 is a half-view in axial section of an alternator withdiagrammatic representation of the stator equipped with a linking pieceaccording to the invention;

[0045]FIG. 2 is a view in perspective of the stator of FIG. 1 withremoval of electrically conducting elements in order to show the slotsof the stator;

[0046]FIG. 3 is a diagrammatic view of the wiring of the windings of thephases;

[0047]FIG. 4 is a view in perspective of the electrically conductingelements of FIG. 1;

[0048] FIGS. 5 to 7 are views similar to FIGS. 2 to 4 for a secondembodiment example according to the invention;

[0049]FIG. 8 is a transverse view of an embodiment variant of thelinking part according to the invention;

[0050]FIG. 9 is a view in transverse section of the stator of FIG. 8;

[0051]FIG. 10 is a transverse view of another embodiment variant of thelinking part according to the invention;

[0052]FIG. 11 is a view in transverse section of the stator of FIG. 10.

[0053]FIG. 12 is a transverse view of another embodiment of theinvention;

[0054]FIG. 13 is a transverse section of the stator of FIG. 12;

[0055]FIG. 14 is a transverse view of a variant of the embodiment of theinvention represented in FIG. 13;

[0056]FIG. 15 is a transverse view of another variant of the embodimentof the invention represented in FIG. 13,

[0057]FIG. 16 is a transverse view of another variant of the embodimentof the invention represented in FIG. 13, and

[0058]FIG. 17 is a transverse view of another embodiment of theinvention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0059] In the figures, identical or similar elements will be allocatedthe same reference signs.

[0060]FIG. 1 represents a multi-phase rotating electric machine in theform of a compact alternator with internal ventilation of thethree-phase type for a motor vehicle with an internal-combustion engine.

[0061] The alternator, going from left to right of FIG. 1, that is tosay from front to rear, includes a drive pulley 1 integral, here by wayof a nut, with the front end of a shaft 2, the rear end of which carriescollector rings (not referenced) belonging to a collector 3. The axis ofthe shaft 2 constitutes the axis of rotation of the machine.

[0062] Centrally, the shaft 2 carries the rotor 4, fixed on and equippedwith an excitation coil 5, the ends of which are linked by wire links tothe collector 3. The rotor 4 here is a claw-type rotor, and thereforeincludes two, front and rear, pole wheels 6, 7 each respectivelycarrying a front 8 and rear 9 fan for, in a given axial bulk,augmentation of the power of the alternator and reduction of the noisefrom it. Each wheel 6, 7 is fixed onto the shaft 2 provided with knurledportions for that purpose, as can be seen in FIG. 1. Each wheel includesa flange perpendicular to the axis of the shaft 2. The excitation coil 5is installed axially between the two wheels 6, 7. At the outer peripheryof the flanges teeth are formed, from the same material, extendingaxially. The teeth have a trapezoidal shape and are given chamferslaterally. The teeth of one of the wheels are turned towards the otherwheel, being offset in angle with respect to the teeth of this otherwheel. There is therefore imbrication of the teeth in such a way that,in one embodiment variant, permanent magnets are interposed between theteeth in order further to augment the power of the machine. For example,profiled grooves are formed in the lateral edges of the teeth in orderto hold the permanent magnets, as described in the document FR-A-2 748248. When the winding 5 is activated, the rotor 4 is magnetised and itis [sic] thus defines pairs of magnetic poles, each pole wheel thenincluding P/2 North poles and P/2 South poles respectively. For furtherdetails, refer to the document EP-A-0 515 259; the teeth of the polewheels each laterally featuring at least one anti-noise chamfer, in theregion of the area where they are rooted to the flange of the pole wheelin question, in order further to reduce noise, especially magneticnoise, from the alternator. Advantageously, each tooth, with respect toan axial axis of symmetry, features two anti-noise chamfers. Thealternator is therefore less noisy.

[0063] The fans 8, 9 include a first series of blades or vanes, whichform ventilation channels between them. Advantageously, two series ofblades of different length are provided, as described in the documentFR-A-2 811 156. Hence at least one blade of the second series of bladesis interposed between two consecutive longer blades of the first seriesof blades. This arrangement makes it possible to reduce the noise fromthe alternator while enhancing the ventilation of it. The blades ariseby cutting-out and folding of a flange fixed, for example by welding orany other means such as crimping, onto the pole wheel 6, 7 in question.As mentioned above, each wheel features axial teeth directed towards theother wheel, with the teeth of one wheel being imbricated into the otherin order to form magnetic poles when the coil 5 is activated by virtueof the collector rings of the collector 3, each in contact with a brush(not referenced) carried by a brush holder 10 also serving as supportfor a voltage regulator (not visible) linked electrically to the brushesin order to regulate the voltage of the coil 5.

[0064] The regulator is linked to a current-rectifying device 11, suchas a diode bridge (two diodes of which can be seen in FIG. 1), itselflinked to the outlets of the phases equipped with windings, which thestator 13 of the alternator includes. The bridge here is of the sametype as that described in the document EP-A-0 743 738, to whichreference should be made for further details. This bridge thereforeincludes a positive heat sink on which are mounted the positive diodes,a negative heat sink, on which are mounted the negative diodes, and aconnector. Here, the negative heat sink consists of the flange of therear bearing 16 of the alternator described below. In a variant, thebridge is of the same type as that described in the document FR 01 09482 filed on Jul. 16, 2001. In this case, the positive heat sinkincludes cooling vanes, which extend in the radial direction of thealternator; the negative diodes carried by the rear bearing being cooledby convection and conduction. This type of bridge is very suitable forthe high-power alternator according to the invention. Thearmature-forming stator 13 surrounds the rotor 4 and features a body 14fitted internally with axial slots 39, 39′ for the passage of the wiresor of the pins which the windings include. In a known way, the body 14here consists of a pack of metal plates each exhibiting slots. Theseoblong-shaped slots constitute grooves when the metal plates are alignedand open out at the inner periphery of the body 14. The body 14surrounds the rotor 4 with a radial gap being present between the innerperiphery of the body 14 and the outer periphery of the rotor 4.

[0065] The windings are arranged in a network in order to form buns 12,12′ at their ends, extending, on the one hand, in axial projection oneither side of the body 14; and, on the other hand, radially above thefans 8, 9.

[0066] These fans 8, 9 extend in the vicinity respectively of a frontbearing 15 and of a rear bearing 16. The bearings 15, 16 are made ofmetal, here being aluminium based. These bearings, in a known way,include claws for fixing the alternator onto a fixed part of the motorvehicle and for electrical linking of the alternator to earth. Thebearings 15, 16 are pierced for internal ventilation of the alternatorby way of the fans 8, 9 when the fans 8, 9—rotor 4—shaft 2 assembly isdriven in rotation by the pulley 1 linked to the engine of the motorvehicle via a transmission device including at least one belt inengagement with the pulley 1. This ventilation makes it possible to coolthe windings of the buns 12, 12′ and the coil 5, as well as the brushholder 10 with its voltage regulator and the rectification device 11.The path followed by the cooling fluid, here air, through the variousapertures of the bearings 15, 16 and the interior of the machine havebeen represented by arrows in FIG. 1.

[0067] This device 11, the brush holder, as well as a pierced protectivecap (not referenced) preferably made of plastic are carried, fixed on,by the rear bearing 16 such that the rear fan 9 is more powerful thanthe front fan 8. In a known way, the bearings 15, 16 are linkedtogether, here with the aid of screws or, in a variant, of tie rodswhich are not visible, so as to form a casing or support intended to bemounted on a fixed part of the vehicle. This support carries the body14.

[0068] The bearings 15, 16 each centrally carry a ball bearing 17, 18for rotational support of the front and rear ends of the shaft 2 passingthrough the bearings in order to carry the pulley 1 and the rings of thecollector 3.

[0069] The blades of the fans 8, 9 extend radially above the housingswhich the bearings 15, 16 feature for mounting of the bearings 17 and 18which are thus ventilated. In a variant, the alternator is cooled by acooling liquid, such as the cooling water from the internal-combustionengine of the motor vehicle; the rear bearing including channels asdescribed, for example, in the document DE-A-100 19 914 to whichreference may be made for further details. The stator in this case ismounted with the use of buffers made of elastic material, for example ofelastomer, on the casing in order to filter the vibration and reducenoise. The same goes for FIG. 1, the buffers with a bracket-shapedcross-section not being referenced.

[0070] These buffers act between the free ends of the peripheral part ofthe bearings, of axial orientation, and the opposite axial ends of thebody 14. These buffers constitute elastic damping means with radial andaxial action for mechanical decoupling of the body 14 of the stator withrespect to the casing consisting of the bearings 15, 16. The bearingsalso each include a transverse flange centrally carrying the ballbearing 17, 18 in question and being connected to the peripheral part inquestion. In a variant, the elastic damping means act in the region ofthe slots 39, 39′ between the edges thereof and the electricallyconducting elements, described below, mounted in them as described inthe document FR 99 16369 filed on Dec. 23, 1999 and published under NoFR-A-2 803 126. In a variant, elastically deformable thermallyconducting resin is interposed radially between the outer periphery ofthe body 14 and the inner periphery of one of the bearings, such as thefront bearing, as described in the document FR 00 13527 filed on Oct. 6,2000. In this case, the coil 5 of the rotor 4 may be constructed on thebasis of a conductor element wound and coated with a linking layer, forexample of the thermosetting type, as described in the document FR-A-2809 546. The coil 5 gives off more heat which is removed via thethermally conducting resin. In a variant, the body 14 is mounteddirectly on the bearings.

[0071] In a variant, the rotor includes salient poles as described inthe document FR 01 00122 filed on Jan. 5, 2001; permanent magnets beingaccommodated in housings formed in the pack of metal plates which therotor includes. These housings are open towards the outer periphery ofthe rotor and closed axially by non-magnetic pieces intended to comeinto abutment against the magnets.

[0072] In FIGS. 2 to 4, the alternator is of the three-phase type andincludes three phases 20 to 22 with, in each case, respectively an inletE1 to E3 and an outlet S1 to S3. The outlets, in a known way, areconnected to the rectification device 11 for the electric current,knowing that the phases of the stator 13 produce an alternating currentwhen the rotor is excited and is driven in rotation by the engine of thevehicle via the pulley 1. For that reason, it is necessary to rectifythe alternating current in order to supply direct current to theelectrical consumer units of the vehicle and to recharge its battery.

[0073] In FIGS. 5 to 7, the alternator is of the six-phase type andtherefore includes, in addition to the phases 20 to 22 constituting afirst series of three phases, a second series of three phases 23 to 25with, in each case, respectively an inlet E′1 to E′3 and an outlet S′1to S′3. The outlets are linked, in the above-mentioned way, to therectification device 11, as described, for example, in theabove-mentioned document EP-A-0 743 738; the connector of the device 11including claws for fixing the outlets belonging to a network ofelectrically conducting regions. The fixing of the outlets to the clawsis achieved, for example, by crimping or welding. Each phase includes atleast one winding comprising electrically conducting elements 37, 38.

[0074] In all cases, the inlets are linked to a neutral point and thealternator for a motor vehicle includes a stator 13 equipped with a body14, carrying several phases 20 to 25 each comprising, on the one hand,an input E1 to E′3 and an outlet S1 to S′3 installed outside the body 14of the stator 13, and, on the other hand, electrically conductingelements 37, 38 which are arranged into a network on either side of thebody 14 of the stator 13 so as to form a first 12 and a second 12′ bunand which pass through the said body. The electrically conductingelements 37, 38 are linked together so as to form the said networks andto connect the inlet of the phase to the outlet of the phase, forming atleast one winding. These conductor elements here are in the shape ofbars. The bars here have a rectangular-shaped cross-section andadvantageously belong to pins. The conductor elements here are fitted inpairs in the radial direction into the slots; the length of the barsbeing parallel to the lateral edges of the slots.

[0075] In order to reduce the length of the inlets and to constitute theneutral point according to the invention, an alternator of the type setout above is characterised in that one of the buns, on one side of thebody 14 of the stator 13, carries three inlets E1 to E3-E′1 to E′3, anelectrically conducting linking part 50 of circumferential orientationlinking together the said inlets E1 to E3 and another 51 the inlets E′1to E′3. Each linking part is formed by an affixed linking piece or byconnected portions of pins.

[0076] The linking part, here of metal, for example of copper, thusmakes it possible to form the neutral point in a compact, simple andeconomic way. This part is light and makes it possible to reduce theweight of the stator. The linking part makes it possible to standardisethe inlets E1 to E3-E′1 to E′3, here of the same length and of identicalcross-section. The linking part advantageously has the samecross-section as that of the inlets.

[0077] Here the inlets and the outlets of the phases have cross-sectionsidentical to those of the electrically conducting elements, especiallyfor economic reasons.

[0078] The linking part 50, 51 is generally linked by welding to thesaid inlets.

[0079] The linking part 50, 51, according to one characteristic, has anannular-sector shape so as to reduce the bulk and the electricalresistance of the stator 13.

[0080] This sector features a length in a circumferentially orientedcircular arc, a weight and a height. Here the height or thickness isless than the width.

[0081] The annular sector constituting the linking part 50, 51 featuresa width of axial orientation so as to reduce the diametral bulk of thestator as much as possible and to avoid any interference with the outerperiphery, of axial orientation, of the support 15, 16 of thealternator. In a variant, the width is oriented radially. In theembodiment represented in FIGS. 2 to 11 this linking part thereforeconsists of an independent piece in the shape of a curved bar.

[0082] This linking piece 50, 51 is covered with a layer of electricallyinsulating material and is bared in the region of the inlets E1 toE3-E′1 to E′3 in order to be welded to them. The piece 50, 51 isenamelled, for example.

[0083] As can be seen for example in FIG. 2, the inlets are welded overthe width of the piece 50, 51.

[0084] More precisely, [lacuna] the inlets having a rectangularcross-section, it is the width of the inlets which is welded to thewidth of the piece 50, 51, that is to say on the flat.

[0085] The inlets E1 to E3 of FIGS. 2 to 4 are installed over acircumference of the same diameter as that over which the outlets S1 toS3 are installed, with a slight clearance being present between thelinking piece and the two outlets S2, S3 which are surrounded by thepiece 50; the other outlet S1 is offset circumferentially with respectto the piece 50.

[0086] In FIGS. 5 to 7, the inlets E′1 to E′3 and the linking piece 50,51 are installed on a circumference of different diameter from that onwhich the outlets S′1 to S3, associated with the said inlets, areinstalled.

[0087] The inlets E′1 to E′3 and the linking piece 50, 51 are installedon a circumference of greater diameter to that on which the outlets S′1to S′3, associated with the said inlets, are installed.

[0088] This arrangement facilitates the connecting of the outlets S′1 toS′3 with the rectification device 11 since the outputs are radiallycloser to the device 11. Furthermore, the fitting of the linking piece50, 51 and its fixing onto the inlets are simpler and quicker.

[0089] Needless to say, it is possible to invert the structures in sucha way that, in a variant, the inlets E1 to E3-E′1 to E′3 and the linkingpiece 50, 51 are installed over a circumference of smaller diameter tothat on which the outlets S1 to S3-S′1 to S′3, associated with the saidinlets, are installed.

[0090] The outlets S1 to S3-S′1 to S′3 belong to the same bun 12, 12′ asthe inlets E1 to E3-E′1 to E′3 and extend in axial projection withrespect to the inlets E1 to E3-E′1 to E′3 equipped with the linkingpiece 50, 51, this in a direction opposite to the body 14 of the stator13.

[0091] In embodiments represented, the outlets are installed at the rearof the stator 13 and are configured, in a known way, to pass through therear bearing 16 so as to be connected to the diode-type rectificationdevice 11. The length of the outlets therefore depends on the positionof the device 11.

[0092] Needless to say, in a variant, the outlets S1 to S3-S′1 to S′3 donot belong to the same bun 12, 12′ as the inlets E1 to E3-E′1 to E′3. Inall cases, the outlets extend in axial projection with respect to thebun in question.

[0093] Here the buns 12, 12′ are axially of the same axial length,especially because of the presence of the fan 9. In a variant, one ofthe buns is axially longer than the other.

[0094] The linking piece may be adjacent to the vertices of theelectrically conducting elements 37, 38, which here are electricallyinsulated with respect to one another and with respect to the pack ofmetal plates, which the stator 13 features, in a known way, in order toform the body 14. To that end, these elements 37, 38 as well as theinlets E1 to E3-E′1 to E′3 and the outlets S1 to S3-S′1 to S′3 arecovered over with a layer of an electrically insulating material. Theseconstituent parts are enamelled, for example.

[0095] The position of the linking piece may vary. The linking piece 50,51 may be installed axially between the vertices of the electricallyconducting elements 37, 38, consisting of the axial ends of theseelements 37, 38 belonging to the bun 12, 12′ in question and the body 14of the stator 13. The linking piece is therefore installed axiallybetween the vertices of the bun and the body 14.

[0096] This is made possible because the linking piece is installed atone of the inner or outer peripheries of the bun in question. In thefigures, the linking piece is installed at the outer periphery of thebun 12 thus partially surrounded by this piece in order to impede theventilation of this bun as little as possible. In a variant, this pieceis installed at the inner periphery of the bun.

[0097] The electrically conducting elements 37, 38, the inlets and theoutlets are in the form of metal bars of rectangular cross-section andthe body 14 of the stator 13, in the above-mentioned way, features apack of metal plates complete with slots 39, 39′ traversed by theelectrically conducting elements 37, 38.

[0098] The conducting elements 37, in the above-mentioned way, are barsof rectangular cross-section section, here shaped into U-shapes andtherefore feature branches mounted by axial threading into the slots 39,39′ and a bottom connecting the branches to the outside of the body 14.The ends of the branches are linked together by welding outside the body14. The spacing between two slots 39, 39′ containing the branchesintended to be welded to one another corresponding to one magnetic-polepitch between a North pole and a South pole of the rotor 4.

[0099] The bottoms of the U-shapes are twisted such that one of thebranches of the U, called upper branch, is mounted in the bottom of aslot while the other branch, called lower branch, is mounted in theregion of the opening-out part of a succeeding slot of the same phase.The conductor elements 37 are therefore mounted in lower and upperlayers in the slots, while being electrically insulated from each other.The electrically conducting elements 37 are mounted in series betweenthe inlets and the outlets in question so as to constitute at least onewinding per phase.

[0100] The windings of the phases are of the undulating type here, suchthat, in a known way, the windings of the phases are offsetcircumferentially with respect to one another.

[0101] The welded ends of the branches and the bottoms of the U-shapesof the electrically conducting elements 37, here in the form of pins,are therefore arranged in a network on either side of the body 14 of thestator 13 so as to form the first bun 12′ and the second bun 12. The bun12, situated at the rear of the alternator, includes the inlets and theoutlets for the phases as well as the bottoms of the U-shapes formingthe heads of the pins 37 constituting the electrically conductingelements. The bun 12′ includes the welded ends of the pins 37 passingaxially through the body 14. This arrangement facilitates manufacture ofthe stator 13.

[0102] In a variant, the pins 37 are in two parts such that the weldsexist in the region of the heads of the pins 37 and of the bun 12.

[0103] Needless to say, the pins and therefore the bars may be of roundor square cross-section. In any event, by virtue of the bars, the buns12, 12′ are of short length.

[0104] In FIGS. 2 to 7, the rotor 4 features pole wheels each equippedwith eight teeth which corresponds to 16 magnetic poles (8 poles perwheel 6, 7) while the stator features 96 slots. Needless to say, thisnumber depends on the applications. For example, it is possible to adoptan arrangement with 12 magnetic poles and 72 slots. In a variant, eachpole wheel 6, 7 includes 7 poles.

[0105] In FIGS. 2 to 4, each phase includes two windings and one pair ofconductor elements 37 is provided per slot 39. Inversion pins are seenat 38, as described in the document WO 92/0657, to which referenceshould be made for further details, for linking the first winding to asecond winding of the same phase. Inversion pins 308 extend axially andcircumferentially. They are each installed below an outlet.

[0106] Hence, by virtue of the inversion pins 38 at the end of a turnround the stator, another slot is entered so as to rejoin the secondwinding. In one embodiment, the windings of the same phase are mountedin adjacent slots. In a known way, as regards the coil, each pair ofadjacent slot [sic] of the same phase is offset from the pair ofadjacent slots following this phase by a number of slots necessary formounting windings of the other phases. The conductor elements aretherefore mounted superimposed in each slot for forming at least onepair of conductor elements mounted superimposed and forming a lowerlayer or inner layer and an upper layer or outer layer.

[0107] A single linking piece 50 is provided for linking the threeinlets E1 to E3 and to constitute the neutral point.

[0108] The windings of the same phase are mounted in series. In avariant, the windings are mounted in parallel such that six phases arepresent as can be seen in FIGS. 5 to 7. In these FIGS. 5 to 7 two pairsof electrically conducting elements 37 are provided, shown superimposedin each slot 39′ and the alternator of the six-phase type thereforeincludes, in addition to the phases 20 to 22 constituting a first seriesof three phases, a second series of three phases 23 to 25 with, in eachcase respectively, an inlet E′1 to E′3 and an outlet S′1 to S′3. Twoseries of three inlets and two series of three outlets are thereforeprovided. The two series of three phases are mounted in parallel in sucha way that two rectification devices are provided, for example withdiodes. These two devices, in one embodiment, are mounted side-by-sideand symmetrically as in the document FR-A-2 687 861.

[0109] In this embodiment, the two series of three phases each include aneutral point as can be seen in FIG. 6, such that two linking pieces 50,51 are provided, each linking together the three inlets of the sameseries of three phases. The linking pieces 50, 51 are offsetcircumferentially with respect to one another, being installed on thesame circumference of larger diameter than that on which the outlets areinstalled.

[0110] In a variant, one of the series includes windings mounted indelta mode, so that only one single linking piece is provided.

[0111] It will be noted that, in FIGS. 2 to 7, the inlets are formed byhalf-pins each including a straight-line central portion passing axiallythrough a slot 39, 39′ and two terminal portions extending on eitherside of the central part. In FIGS. 2 to 4 the inlets are offsetcircumferentially with respect to the outlets, while, in FIGS. 5 to 7,the inlets and the outlets are aligned radially. In all cases, theoutlets and the inlets belong to a bar passing through the body 14.

[0112] Each terminal portion of an inlet includes an inclined part beingconnected to the central portion and extended by a straight-line freepart. These are therefore the free and straight-line parts of axialorientation which are intended to be welded onto the linking piece 50,51. The inlets belong to branches mounted at the outer periphery of theslots 39, 39′.

[0113] FIGS. 8 to 16 show several variants of the arrangement of thelinking parts 50, 51.

[0114] In the variant represented in FIGS. 8 and 9, the terminal part ofthe inlets is shorter, such that the electrical resistance is furtherreduced. Each linking part 50, 51 is formed by a piece in the shape ofan annular segment which is welded by its width (on the flat) onto theappropriate lateral face of each terminal part. It results therefromthat the linking piece 50 is adjacent to the axial end in question ofthe body 14 of the stator.

[0115] In the variant represented in FIGS. 10 and 11, the freestraight-line ends of each terminal part of the inlets and [sic] arecurved over in the circumferential or peripheral direction andconstitute claws onto which a linking piece is then welded. It is thethickness of the piece which serves for the welding; the clawsincreasing the area for welding.

[0116] It will be noted that this piece is situated in the region of thevertices of the buns, which separates it from the windings of thephases.

[0117] This solution is more bulky axially, but is favourable forventilation.

[0118] In the embodiment represented in FIGS. 12 and 13, two firstneutral inlets are linked by a pin 160 including a portion extendingcircumferentially and being in one piece with the inclined portions oftwo pins forming two inlets E2-E3 which follow each other at theperiphery of the bun. The third neutral inlet E1 includes an end portionwhich is curved over in the circumferential direction. It extends as faras the part 160 so as to be able to be linked to it by a singleconnecting point produced, for example, in the form of an electron-beamweld 162. The welding is therefore carried out, regarding therectangular cross-section of the pin 160, in terms of the length of thepin. Hence, it is possible to connect the neutral point with a singleweld linking only two specific conductors, thus increasing thereliability of the electrical connection. It is observed that the endportion 160′ is welded to the face of the part 160 which is axiallyoutwards.

[0119] In a variant, the portion 160′ of the third neutral inlet E1 canbe extended beyond the weld point by a free portion of axial orientation163 of short length, as in FIG. 14, or of long length, as in FIG. 15.This latter arrangement is particularly advantageous for linking thethree inlets to the current-rectification device 11.

[0120] In a variant, represented in FIG. 16, the two inlets E2, E3,linked by the peripheral pin portion 160, are not consecutive followingthe periphery of the bun (12, 12′), the third inlet E1 being interposedbetween them. The latter, as in FIG. 12, includes a peripheral endportion 160 [sic], connected under the portion 160.

[0121] In the variant of FIGS. 12 to 16, in order to constitute aneutral point, two pieces are connected by a weld point.

[0122] In another embodiment represented in FIG. 17, the linking part50, 51 constitutes an extension of a straight-line part of one inlet,here E1, passing axially through a slot 39, 39′. The linking part takesthe form of an annular sector of axial orientation to which the twoother inlets E2, E3 come to be connected, for example by welding. Forthat purpose, the end of each inlet E2, E3 is curved over in such a wayas to form a fixing claw parallel to the part 50, 51, under the latterin the axial direction of the stator. It should be noted that the part50, 51 is situated in the region of the vertex of the bun. It ispossible, in this way, to connect the neutral point with two weldslinking three conductors.

[0123] Needless to say, other methods of constituting the neutral may beenvisaged, by applying the principle which has just been described. Inthe same way as for the windings, it is possible to adopt the provisionsdescribed in the document FR 01 13553 filed on Oct. 19, 2001 in order tohave pin heads of the same length. Hence, four layers of electricallyconducting elements are provided per slot in the radial direction as inFIGS. 5 to 7. The two upper layers of a first slot belong to the sameupper pair of electrically conducting elements and the other two lowerlayers to a second lower pair of electrically conducting elements. Theupper pair (the upper branches of the pins) is linked by the bottoms ofthe U-shapes of the pins to a lower pair (the lower branches of the samepins) placed in a second consecutive slot of the same phase. The lowerpair of the first slot is linked by the bottom of the U-shapes of thepins to the upper pair placed in a third consecutive slot of the samephase; the second and the third slots being arranged symmetrically oneither side of the first slot, being separated from it by a number ofslots necessary for the installation of the electrically conductingelements of the other phases.

[0124] Needless to say, four electrically conducting elements, in avariant, are mounted in each slots [sic] in pairs as described in thedocument WO 92/06527 in the above-mentioned way.

[0125] Likewise, in a variant, the alternator is an alternator/starter,that is to say a reversible machine constituting an alternator when thepulley is driven by the engine of the motor vehicle, or a starter fordriving the engine of the vehicle via the pulley as described, forexample, in the document FR-A-2 806 224. In this case, one of thebearings 15, 16 carries at least one sensor, for example of the magnetictype, in order to detect the passing of a magnetic target carried by therotor.

[0126] The rectification bridge is then a rectification and controlbridge, which, in one embodiment, is installed outside the reversiblealternator. The phase outlets are then linked to a connector carried bythe alternator and linked to the rectification and control device via acable. For further details, refer to this document.

[0127] The electric machine according to the invention with a linkingpart is a high-power, compact, low-noise and well-cooled machine.

1. Alternator for a motor vehicle including a stator (13) equipped witha body (14) carrying several phases (20 to 25) each comprising, on theone hand, an inlet (E1 to E′3) and an outlet (S1 to S′3) installedoutside the body (14) of the stator (13), and, on the other hand,electrically conducting elements (37, 38), which are arranged in anetwork on either side of the body (14) of the stator (13) so as to forma first (12) and a second (12′) bun and which pass through the saidbody, in which the electrically conducting elements (37, 38) are linkedtogether to form the said networks and connect the inlet of the phase tothe outlet of the phase by forming at least one winding, characterisedin that one of the buns (12, 12′), on one side of the body (14) of thestator (13), carries three inlets (E1 to E3-E′1 to E′3), and anelectrically conducting linking part (50, 51) of circumferentialorientation linking the said inlets electrically together.
 2. Alternatoraccording to claim 1, characterised in that the linking part (50, 51) islinked by welding to at least one of the said inlets.
 3. Alternatoraccording to claim 1, characterised in that the linking part (50, 51)has an annular-sector shape.
 4. Alternator according to claim 3,characterised in that the linking part (50, 51) has an annular-sectorshape mounted at the outer periphery of the bun (12, 12′) carrying thesaid inlets and in that the width of the linking part (50, 51) is ofaxial orientation.
 5. Alternator according to claim 2, characterised inthat the linking part (50, 51) is installed axially between the verticesof the electrically conducting elements (37, 38) consisting of the axialends of these elements (37, 38) belonging to the bun (12, 12′) inquestion, and the body (14) of the stator (13).
 6. Alternator accordingto claim 2, characterised in that the linking part (50, 51) is installedaxially at the vertex of the electrically conducting elements (37, 38)consisting of the axial ends of these elements (37, 38) belonging to thebun (12, 12′) in question.
 7. Alternator according to claim 1,characterised in that the linking part is a linking piece (50, 51)linking the three inlets (E1 to E3-E1′ to E3′).
 8. Alternator accordingto claim 7, characterised in that the inlets (E1 to E3-E′1 to E′3) eachcomprise a free part of axial orientation, the linking piece (50, 51)linking these free parts.
 9. Alternator according to claim 7,characterised in that the inlets (E1 to E3-E′1 to E′3) each comprise afree part of circumferential orientation, the linking piece (50, 51)linking these free parts.
 10. Alternator according to claim 1,characterised in that two inlets from among [sic] (E1 to E3-E′1 to E′3)are linked by a pin (160), the linking part (50, 51) consisting of anend portion (160′) of the third inlet curved over in the circumferentialdirection and being welded onto the pin (160).
 11. Alternator accordingto claim 10, characterised in that the linking part (50, 51) is extendedby a free portion of axial orientation (163).
 12. Alternator accordingto claim 1, characterised in that the linking part (50, 51) constitutesa circumferential extension of one of the three inlets (E1 to E3-E′1 toE′3).
 13. Alternator according to claim 1, characterised in that theelectrically conducting elements (37, 38), the inlets (E1 to E′3), theoutlets (S1 to S′3) and the electrical linking part (50, 51) are in theform of bars of square or rectangular cross-section.
 14. Alternatoraccording to claim 1, characterised in that the linking part is producedon the basis of an electrically conducting element.